SparseLU_column_dfs.h
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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2012 Désiré Nuentsa-Wakam <desire.nuentsa_wakam@inria.fr>
5 //
6 // This Source Code Form is subject to the terms of the Mozilla
7 // Public License v. 2.0. If a copy of the MPL was not distributed
8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9 
10 /*
11 
12  * NOTE: This file is the modified version of [s,d,c,z]column_dfs.c file in SuperLU
13 
14  * -- SuperLU routine (version 2.0) --
15  * Univ. of California Berkeley, Xerox Palo Alto Research Center,
16  * and Lawrence Berkeley National Lab.
17  * November 15, 1997
18  *
19  * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
20  *
21  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
22  * EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
23  *
24  * Permission is hereby granted to use or copy this program for any
25  * purpose, provided the above notices are retained on all copies.
26  * Permission to modify the code and to distribute modified code is
27  * granted, provided the above notices are retained, and a notice that
28  * the code was modified is included with the above copyright notice.
29  */
30 #ifndef SPARSELU_COLUMN_DFS_H
31 #define SPARSELU_COLUMN_DFS_H
32 
33 template <typename Scalar, typename StorageIndex> class SparseLUImpl;
34 namespace Eigen {
35 
36 namespace internal {
37 
38 template<typename IndexVector, typename ScalarVector>
40 {
41  typedef typename ScalarVector::Scalar Scalar;
44  : m_jcol(jcol), m_jsuper_ref(jsuper), m_glu(glu), m_luImpl(luImpl)
45  {}
46  bool update_segrep(Index /*krep*/, Index /*jj*/)
47  {
48  return true;
49  }
50  void mem_expand(IndexVector& lsub, Index& nextl, Index chmark)
51  {
52  if (nextl >= m_glu.nzlmax)
53  m_luImpl.memXpand(lsub, m_glu.nzlmax, nextl, LSUB, m_glu.num_expansions);
54  if (chmark != (m_jcol-1)) m_jsuper_ref = emptyIdxLU;
55  }
56  enum { ExpandMem = true };
57 
62 };
63 
64 
92 template <typename Scalar, typename StorageIndex>
94  BlockIndexVector lsub_col, IndexVector& segrep, BlockIndexVector repfnz, IndexVector& xprune,
95  IndexVector& marker, IndexVector& parent, IndexVector& xplore, GlobalLU_t& glu)
96 {
97 
98  Index jsuper = glu.supno(jcol);
99  Index nextl = glu.xlsub(jcol);
100  VectorBlock<IndexVector> marker2(marker, 2*m, m);
101 
102 
103  column_dfs_traits<IndexVector, ScalarVector> traits(jcol, jsuper, glu, *this);
104 
105  // For each nonzero in A(*,jcol) do dfs
106  for (Index k = 0; ((k < m) ? lsub_col[k] != emptyIdxLU : false) ; k++)
107  {
108  Index krow = lsub_col(k);
109  lsub_col(k) = emptyIdxLU;
110  Index kmark = marker2(krow);
111 
112  // krow was visited before, go to the next nonz;
113  if (kmark == jcol) continue;
114 
115  dfs_kernel(StorageIndex(jcol), perm_r, nseg, glu.lsub, segrep, repfnz, xprune, marker2, parent,
116  xplore, glu, nextl, krow, traits);
117  } // for each nonzero ...
118 
119  Index fsupc;
120  StorageIndex nsuper = glu.supno(jcol);
121  StorageIndex jcolp1 = StorageIndex(jcol) + 1;
122  Index jcolm1 = jcol - 1;
123 
124  // check to see if j belongs in the same supernode as j-1
125  if ( jcol == 0 )
126  { // Do nothing for column 0
127  nsuper = glu.supno(0) = 0 ;
128  }
129  else
130  {
131  fsupc = glu.xsup(nsuper);
132  StorageIndex jptr = glu.xlsub(jcol); // Not yet compressed
133  StorageIndex jm1ptr = glu.xlsub(jcolm1);
134 
135  // Use supernodes of type T2 : see SuperLU paper
136  if ( (nextl-jptr != jptr-jm1ptr-1) ) jsuper = emptyIdxLU;
137 
138  // Make sure the number of columns in a supernode doesn't
139  // exceed threshold
140  if ( (jcol - fsupc) >= maxsuper) jsuper = emptyIdxLU;
141 
142  /* If jcol starts a new supernode, reclaim storage space in
143  * glu.lsub from previous supernode. Note we only store
144  * the subscript set of the first and last columns of
145  * a supernode. (first for num values, last for pruning)
146  */
147  if (jsuper == emptyIdxLU)
148  { // starts a new supernode
149  if ( (fsupc < jcolm1-1) )
150  { // >= 3 columns in nsuper
151  StorageIndex ito = glu.xlsub(fsupc+1);
152  glu.xlsub(jcolm1) = ito;
153  StorageIndex istop = ito + jptr - jm1ptr;
154  xprune(jcolm1) = istop; // initialize xprune(jcol-1)
155  glu.xlsub(jcol) = istop;
156 
157  for (StorageIndex ifrom = jm1ptr; ifrom < nextl; ++ifrom, ++ito)
158  glu.lsub(ito) = glu.lsub(ifrom);
159  nextl = ito; // = istop + length(jcol)
160  }
161  nsuper++;
162  glu.supno(jcol) = nsuper;
163  } // if a new supernode
164  } // end else: jcol > 0
165 
166  // Tidy up the pointers before exit
167  glu.xsup(nsuper+1) = jcolp1;
168  glu.supno(jcolp1) = nsuper;
169  xprune(jcol) = StorageIndex(nextl); // Initialize upper bound for pruning
170  glu.xlsub(jcolp1) = StorageIndex(nextl);
171 
172  return 0;
173 }
174 
175 } // end namespace internal
176 
177 } // end namespace Eigen
178 
179 #endif
Matrix3f m
SCALAR Scalar
Definition: bench_gemm.cpp:46
Namespace containing all symbols from the Eigen library.
Definition: jet.h:637
Expression of a fixed-size or dynamic-size sub-vector.
EIGEN_DEFAULT_DENSE_INDEX_TYPE Index
The Index type as used for the API.
Definition: Meta.h:74
SparseLUImpl< Scalar, StorageIndex > & m_luImpl
Index column_dfs(const Index m, const Index jcol, IndexVector &perm_r, Index maxsuper, Index &nseg, BlockIndexVector lsub_col, IndexVector &segrep, BlockIndexVector repfnz, IndexVector &xprune, IndexVector &marker, IndexVector &parent, IndexVector &xplore, GlobalLU_t &glu)
Performs a symbolic factorization on column jcol and decide the supernode boundary.
A matrix or vector expression mapping an existing expression.
Definition: Ref.h:281
column_dfs_traits(Index jcol, Index &jsuper, typename SparseLUImpl< Scalar, StorageIndex >::GlobalLU_t &glu, SparseLUImpl< Scalar, StorageIndex > &luImpl)
void mem_expand(IndexVector &lsub, Index &nextl, Index chmark)
SparseLUImpl< Scalar, StorageIndex >::GlobalLU_t & m_glu
The matrix class, also used for vectors and row-vectors.


gtsam
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autogenerated on Tue Jul 4 2023 02:35:58